const fp = require('lodash/fp')

const cars = [
  {
    name: 'Ferrari FF',
    horsepower: 660,
    dollar_value: 700000,
    in_stock: true
  },
  {
    name: 'Spyker C12 Zagato',
    horsepower: 650,
    dollar_value: 648000,
    in_stock: false
  },
  {
    name: 'Jaguar XKR-S',
    horsepower: 550,
    dollar_value: 132000,
    in_stock: false
  },
  {
    name: 'Audi R8',
    horsepower: 525,
    dollar_value: 114200,
    in_stock: false
  },
  {
    name: 'Aston Martin One-77',
    horsepower: 750,
    dollar_value: 1850000,
    in_stock: true
  },
  {
    name: 'Pagani Huayra',
    horsepower: 700,
    dollar_value: 1300000,
    in_stock: false
  }
]

//练习1:使用函数组合fp.flowRight()重新实现

let isLastInstock = fp.flowRight(fp.prop('in_stock'), fp.last)

// console.log(isLastInstock(cars))

//练习2：使用fp.flowRight()、fp.prop()和fp.first()获取第一个car的name

let getFirstName = fp.flowRight(fp.prop('name'), fp.first)

// console.log(getFirstName(cars))

//练习3：使用帮助函数_average重构averageDollarValue，使用函数组合的方式实现

let _average = function(xs) {
  return fp.reduce(fp.add, 0, xs) / xs.length
}


let averageDollarValue = fp.flowRight(_average, fp.map(item => item.dollar_value))

// console.log(averageDollarValue(cars))

//练习4：使用flowRight写一个sanitizeNames()函数，返回一个下划线链接的小写字符串，
//把数组中的name转换成为这种形式:例如：sanitizeNames(["Hello World"]) => ["hello_world"]

let _underscore = fp.replace(/\W+/g, '_')

let sanitizeNames = fp.flowRight(_underscore, fp.toLower)

// console.log(sanitizeNames('Hello World'))